Hair loss is common in macaque colonies. Hair loss may be mediated by normal factors (e.g., season) or may serve as a biomarker for health-related disorders (e.g., stress and allergies). We examined hair loss and hair cortisol concentrations in 140 (83 female) rhesus macaques from four primate centers, all of whom had been sampled twice approximately 8 months apart. If hair loss is a biomarker for stress, we predicted that hair cortisol levels should increase with hair loss and decrease with regrown hair. Surprisingly, hair loss condition changed little across sampling periods with only 12 (9%) monkeys showing a greater than 10% loss of hair and 30 (21%) monkeys showing a greater than 10% regrowth of hair. Hair cortisol was correlated across samples (r=.33, p<.001) and was larger in the monkeys whose hair loss condition remained the same (r=.48, p<.001). Regrowth of hair was significantly associated with a decrease in hair cortisol levels in females (F=2.85, p=0.05), but loss of hair in females was not associated with an increase in hair cortisol levels. At one facility, some monkeys went from indoor to outdoor housing whereas others remained indoors. Loss/gain of hair was equally spread across housing condition. Hair cortisol levels did not change when monkeys were moved outdoors. Hair loss and hair cortisol values were stable over eight months under several environmental conditions.